The present invention is concerned with a chemical agent for the rapid elimination of active chlorine compounds, especially chloramine, and for the simultaneous binding of ammonia and heavy metal ions in water supplies such as drinking water, or fresh or sea water used for the breeding and maintenance of aquatic animals in aquaria, ponds, streams, circulating systems and transport containers.
Especially in countries in warmer climates, there is increasing use of chloramine (H.sub.2 NCl) in place of chlorine, hypochlorites, chlorine dioxide and similar active chlorine compounds for the disinfection of drinking water to eliminate problems caused by micro-organisms. Thus, for example, in some of the United States, chloramine concentrations are used in the range of from 0.2 to 2.5 mg/liter.
These concentrations which are fully acceptable to humans prove, in the case of aquarium fish, to be initially toxic to highly toxic as shown by a comparison with the average toxicity data:
LC.sub.0 =0.1-0.15 mg/liter H.sub.2 NCl PA1 LC.sub.50 =0.3-0.35 mg/liter H.sub.2 NCl PA1 LC.sub.100 &gt;0.8 mg/liter H.sub.2 NCl
Refilling an aquarium or even replacing the greater than 10% of the water in an aquarium with drinking water containing chloramine may prove fatal to all of the fish in the aquarium tank. The lethal, toxic action of chloramine in the water is seen usually within 5 to 30 minutes.
This situation is made more difficult by the fact that in many municipal waterworks rather than adding pure chloramine to the drinking water supply, sodium hypochlorite solution or chlorine are added together with ammonia. Chloramine is thus generated in situ according to the following equations: EQU Cl.sub.2 +NH.sub.3 .fwdarw.H.sub.2 NCl+H.sup.+ +Cl.sup.-
as well as EQU HOCl+NH.sub.3 .fwdarw.H.sub.2 NCl+H.sub.2 O
Ammonia is frequently added to the drinking water supply in excess so that drinking water treated in this manner also contains ammonia as well as chloramine.
One known method for the removal of chloramine from water supplies is the reduction of chloramine by the action of sodium thiosulfate. However, the ammonia which is liberated from the reduction of the chloramine according to the equation: EQU H.sub.2 NCl+H.sup.+ +2e.sup.-.fwdarw.NH.sub.3 +Cl.sup.-
chloramine reducer ammonia chloride cannot be bound by sodium thiosulfate. The removal of ammonia is also of great importance to aquarists and fish breeders since it is known that ammonia is also a strong fish poison. Therefore, when an agent such as sodium thiosulfate is used to treat chloramine, there is also the additional need to use an active agent such as zeolites to adsorb the ammonia. Heavy metals, on the other hand, can be bound by thiosulfate ions to give thiosulfate complexes, their toxicity thereby being reduced.
The sodium bisulfite adduct of formaldehyde, sodium hydroxymethylsulfonate, Na.sup.+ HO-CH.sub.2 SO.sub.3.sup.-, is another agent which is known for the reduction of chloramine and for binding ammonia.
Therefore it is an object of the present invention to provide agents which in a single step rapidly reduce chloramine, simultaneously bind ammonia, and are also capable of binding heavy metal ions in order to prepare drinking water, or fresh or sea water for the breeding and maintenance of aquatic animals in aquaria, ponds, streams, circulating systems, or transport containers.